Shaking screens on which images are displayed can enhance displayed images on the screen. Viewers seated close to the screen may see screen surface-texture detail on specially formulated screens, which can provide optimal reflection of projected images. When loudspeakers are positioned behind the screen, the screen can be constructed with perforations to allow the sound from the loudspeakers to pass through the screen more effectively. Viewers seated close to a screen with perforations may see perforated edges. If a screen has a seam, the seam edge may become noticeable. By shaking the screen, screen artifacts that have edges can be blurred to make these features less visible or non-visible.
Projecting an image on a stationary screen using a coherent light source, such as a laser light source, can result in visual artifacts (known as speckle) in the image area. By shaking the screen surface on which an image is projected, speckle artifacts can be reduced or eliminated.
To ensure speckle or screen surface artifacts are reduced over all of the image area on the screen, all of the screen area can be shaken. It can be desirable to have more than one point or source of screen vibration to vibrate all of the image area of the screen. Screens can have a large surface area made of a material, such as vinyl, that absorbs sufficient vibration energy imparted to the screen such that the screen requires multiple vibration locations.
Using multiple vibrating sources to vibrate the screen, however, can introduce problems.